Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 1081: What is the primary cardiotoxic effect of bupivacaine?

A. Depressed pacemaker activity (Correct Answer)
B. Toxic compound damaging myocardial cells
C. Depressed neural control on heart
D. Vascular thrombosis and Myocardial ischemia

Explanation: ***Depressed pacemaker activity*** - **Bupivacaine** is a potent **local anesthetic** that blocks voltage-gated **sodium channels** in myocardial cells with **high affinity** and **slow dissociation kinetics**. - This prolonged channel blockade leads to decreased cardiac excitability and **depressed automaticity** of pacemaker cells, particularly affecting the **SA node** and **His-Purkinje system**. - Results in slowing of the **heart rate**, **bradyarrhythmias**, **conduction blocks**, and potentially **ventricular arrhythmias** or **asystole**. - Bupivacaine is **more cardiotoxic** than other local anesthetics due to its **lipophilicity** and prolonged binding to cardiac sodium channels. *Toxic compound damaging myocardial cells* - While **bupivacaine** is cardiotoxic, its primary mechanism is not direct **cellular damage** through cytotoxic effects, oxidative stress, or cell membrane lysis. - The toxicity is predominantly due to **electrophysiological effects** on ion channels, interfering with normal cardiac conduction and contractility. *Depressed neural control on heart* - **Bupivacaine's** cardiotoxicity primarily affects the **myocardium directly** through sodium channel blockade, rather than indirectly through the **autonomic nervous system**. - Although high systemic concentrations can affect the **central nervous system** (causing seizures and CNS depression), the direct cardiac effects occur independently of neural influence. *Vascular thrombosis and Myocardial ischemia* - **Bupivacaine** cardiotoxicity does not typically involve formation of **thrombi** or mechanisms leading to **myocardial ischemia** through coronary artery occlusion. - Its effects are predominantly on the **electrical conduction system**, **myocardial contractility**, and **cardiac ion channels**, not the vascular supply to the heart.

Question 1082: Which of the following is a centrally acting antihypertensive drug?

A. Phenoxybenzamine
B. Propranolol
C. Prazosin
D. Methyldopa (Correct Answer)

Explanation: ***Methyldopa*** - **Methyldopa** is a **prodrug** that is converted to **alpha-methylnorepinephrine** in the brain, which then stimulates **alpha-2 adrenergic receptors** in the brainstem. - This stimulation reduces **sympathetic outflow** from the central nervous system, leading to decreased heart rate, stroke volume, and peripheral vascular resistance, thus lowering blood pressure. *Phenoxybenzamine* - **Phenoxybenzamine** is an **alpha-1 and alpha-2 adrenergic receptor antagonist** (non-selective alpha blocker) that primarily acts peripherally. - It causes **vasodilation** by blocking alpha-1 receptors on smooth muscle, which reduces peripheral vascular resistance. *Propranolol* - **Propranolol** is a **non-selective beta-blocker** that primarily acts on peripheral beta-adrenergic receptors. - It reduces heart rate and cardiac output by blocking **beta-1 receptors** in the heart and can also affect beta-2 receptors in the lungs and vasculature. *Prazosin* - **Prazosin** is a **selective alpha-1 adrenergic receptor antagonist** that acts primarily on peripheral blood vessels. - It causes **vasodilation** in both arteries and veins by blocking alpha-1 receptors, which reduces both preload and afterload, lowering blood pressure.

Question 1083: Which statin is considered most potent based on mg-to-mg LDL reduction capability?

A. Simvastatin
B. Pravastatin
C. Rosuvastatin (Correct Answer)
D. Atorvastatin

Explanation: ***Rosuvastatin*** - **Rosuvastatin** is known for its high potency, achieving significant **LDL-C reduction** at relatively low doses. - It is often considered the most potent statin on a **milligram-to-milligram basis**. *Simvastatin* - **Simvastatin** is a moderate-intensity statin, not as potent as rosuvastatin or atorvastatin in reducing LDL-C. - While effective, it typically requires higher doses to achieve comparable **LDL-C reductions** seen with high-potency statins. *Pravastatin* - **Pravastatin** is a hydrophilic statin, generally considered to be of lower potency compared to other statins like rosuvastatin and atorvastatin. - It is often used in patients with **hepatic dysfunction** due to its different metabolic profile but offers less aggressive **LDL-C reduction**. *Atorvastatin* - **Atorvastatin** is a high-intensity statin, very effective in reducing LDL-C, and often used for aggressive lipid lowering. - While highly potent, **atorvastatin** is generally considered slightly less potent than **rosuvastatin** on a mg-to-mg basis, though both are used for high-intensity lipid therapy.

Question 1084: Which antilipidemic drug reduces cholesterol levels by inhibiting cholesterol absorption?

A. Ezetimibe (Correct Answer)
B. Orlistat
C. Cholestyramine
D. Statins

Explanation: ***Ezetimibe*** - **Ezetimibe** selectively inhibits the **Niemann-Pick C1-Like 1 (NPC1L1) protein**, which is responsible for plant sterol and cholesterol absorption in the small intestine. - This action leads to a reduction in **LDL-C** levels by decreasing the amount of cholesterol available to the liver. *Orlistat* - **Orlistat** is a **lipase inhibitor** that prevents the absorption of dietary fats by inhibiting gastric and pancreatic lipases. - While it aids in weight loss and can indirectly improve lipid profiles, its primary mechanism is *not* direct inhibition of cholesterol absorption. *Cholestyramine* - **Cholestyramine** is a **bile acid sequestrant** that binds to bile acids in the intestine, preventing their reabsorption. - This increases the excretion of bile acids, prompting the liver to synthesize more bile acids from cholesterol, thereby lowering cholesterol levels, but it does *not* directly inhibit cholesterol absorption. *Statins* - **Statins** (HMG-CoA reductase inhibitors) are considered first-line agents for lowering cholesterol by inhibiting the **rate-limiting step in cholesterol synthesis** in the liver. - Their primary action is to reduce endogenous cholesterol production, not to block cholesterol absorption from the gut.

Question 1085: Which of the following statements about Conivaptan is correct?

A. It is a vasopressin antagonist. (Correct Answer)
B. It selectively acts on V2 receptors.
C. It is administered orally.
D. All of the options.

Explanation: ***It is a vasopressin antagonist.*** * **Conivaptan** is a non-peptide, dual **vasopressin V1A and V2 receptor antagonist**, meaning it blocks the action of vasopressin. * By blocking vasopressin, it promotes **aquaresis** (excretion of solute-free water), which is beneficial in conditions like **hyponatremia**. * *It selectively acts on V2 receptors.* * **Conivaptan** is a **dual antagonist**, blocking both **V1A and V2 receptors**, not just V2. * **Tolvaptan**, in contrast, is a selective **V2 receptor antagonist**. * *It is administered orally.* * **Conivaptan** is typically administered intravenously, particularly in hospital settings for acute hyponatremia. * **Tolvaptan** is the orally administered vasopressin antagonist. * *All of the options.* * Since Conivaptan is not selectively acting on V2 receptors and is not administered orally, this option is incorrect.

Question 1086: Which of the following potassium-sparing diuretics was the first to be shown to reduce cardiac mortality in chronic heart failure patients?

A. Spironolactone (Correct Answer)
B. Amiloride
C. Triamterene
D. Eplerenone

Explanation: ***Spironolactone*** - **Spironolactone** was the first potassium-sparing diuretic shown to reduce **cardiac mortality** in patients with **chronic heart failure** in the **RALES trial** (Randomized Aldactone Evaluation Study). - Its beneficial effects in heart failure are primarily attributed to its **aldosterone receptor antagonist** properties, which counteract the harmful effects of aldosterone on the myocardium and vasculature, rather than just its diuretic effect. *Amiloride* - **Amiloride** is a potassium-sparing diuretic that works by directly inhibiting **epithelial sodium channels (ENaC)** in the collecting duct. - While it helps in potassium conservation, it has not been shown to significantly reduce cardiac mortality in chronic heart failure patients in clinical trials. *Triamterene* - **Triamterene** is another potassium-sparing diuretic that also directly inhibits **ENaC** in the collecting duct, similar to amiloride. - Like amiloride, it is used to prevent hypokalemia but lacks evidence for significant **cardiac mortality reduction** in chronic heart failure. *Eplerenone* - **Eplerenone** is a selective **aldosterone receptor antagonist**, similar to spironolactone, with fewer hormonal side effects. - While it has been shown to reduce **cardiac mortality** in chronic heart failure (e.g., in the EMPHASIS-HF trial), it was introduced later than spironolactone and was not the *first* to demonstrate this benefit.

Question 1087: Which of the following statements about dopamine is false?

A. Improves renal perfusion
B. Causes Vasoconstriction
C. Causes increase in GI Ischemia (Correct Answer)
D. Positive ionotropic

Explanation: ***Causes increase in GI Ischemia*** (FALSE Statement) - This statement is **incorrect and misleading** as dopamine does not primarily "cause increase in GI ischemia" - While dopamine at **higher doses** can cause **splanchnic vasoconstriction** via alpha-1 receptors, this is not characterized as "causing GI ischemia" in standard pharmacology - GI ischemia is a potential adverse effect in susceptible patients, but not a primary pharmacological effect or standard clinical description of dopamine *Positive inotropic* (TRUE Statement) - Dopamine is a **catecholamine** with dose-dependent effects; at **moderate doses (5-10 mcg/kg/min)**, it stimulates **beta-1 adrenergic receptors** in the heart - This beta-1 stimulation leads to increased **myocardial contractility** and **heart rate**, thus exerting a **positive inotropic effect** - This is a well-established therapeutic effect of dopamine *Improves renal perfusion* (TRUE Statement) - At **low doses (0.5-3 mcg/kg/min)**, dopamine selectively activates **dopamine-1 (D1) receptors** in the renal vasculature - This activation causes **renal vasodilation**, leading to increased **renal blood flow**, improved **glomerular filtration rate**, and enhanced **sodium excretion** - This "renal dose" effect is a classic pharmacological property of dopamine *Causes Vasoconstriction* (TRUE Statement) - At **high doses (>10 mcg/kg/min)**, dopamine primarily stimulates **alpha-1 adrenergic receptors** - This leads to generalized **vasoconstriction**, increasing **systemic vascular resistance** and **blood pressure** - This dose-dependent alpha effect is well-documented

Question 1088: Which of the following medications is known to cause increased renin levels with prolonged use?

A. Clonidine
B. Enalapril (Correct Answer)
C. Methyldopa
D. Propranolol

Explanation: ***Enalapril*** - **Enalapril** is an **ACE inhibitor** which blocks the conversion of angiotensin I to angiotensin II, leading to decreased levels of angiotensin II [1]. - Reduced angiotensin II levels remove the **negative feedback** on renin release from the juxtaglomerular cells, thus increasing renin secretion [1], [2]. *Clonidine* - Clonidine is a **central alpha-2 adrenergic agonist** that reduces sympathetic outflow from the central nervous system. - This reduction in sympathetic activity leads to a **decrease in renin release**, as sympathetic stimulation normally promotes renin secretion [3]. *Methyldopa* - Methyldopa is a **central alpha-2 adrenergic agonist** that works similarly to clonidine by reducing sympathetic tone. - It consequently causes a **decrease in plasma renin activity** due to reduced sympathetic stimulation of the juxtaglomerular apparatus [3]. *Propranolol* - Propranolol is a **non-selective beta-blocker** that blocks beta-1 receptors in the juxtaglomerular cells of the kidney. - This blockade **inhibits the release of renin** stimulated by sympathetic activity, leading to reduced renin levels [3].

Question 1089: Hypertension is not seen with which of the following?

A. NSAIDs
B. Erythropoietin
C. Cyclosporine
D. L–dopa (Correct Answer)

Explanation: ***L–dopa*** - **L-dopa** can cause **orthostatic hypotension**, a drop in blood pressure upon standing, rather than sustained hypertension. - Its primary cardiovascular side effects are usually related to **dopaminergic stimulation**, leading to arrhythmias or orthostatic changes. *Cyclosporine* - **Cyclosporine** frequently causes **hypertension** by inducing vasoconstriction, increasing sympathetic activity, and affecting renal sodium handling. - It can lead to **renal impairment**, which further contributes to blood pressure elevation. *NSAIDs* - **NSAIDs** can cause **hypertension** by inhibiting renal prostaglandin synthesis, leading to sodium and water retention. - This effect can be particularly significant in patients with pre-existing hypertension or renal dysfunction. *Erythropoietin* - **Erythropoietin** commonly causes **hypertension**, especially when there is a rapid rise in hemoglobin or hematocrit levels. - The mechanism is thought to involve increased peripheral vascular resistance and changes in nitric oxide homeostasis.

Question 1090: A 50-year-old male with type 2 diabetes mellitus is found to have a 24-hour urinary albumin level of 250 mg. Which of the following drugs may be used to retard the progression of renal disease?

A. Enalapril (Correct Answer)
B. Amiloride
C. Aspirin
D. Hydrochlorothiazide

Explanation: ***Enalapril*** - **Enalapril**, an ACE inhibitor, is indicated for **diabetic nephropathy** because it reduces intraglomerular pressure and proteinuria, thereby retarding the progression of renal disease. - Its nephroprotective effects are mediated through effects on the **renin-angiotensin-aldosterone system**. *Hydrochlorothiazide* - **Hydrochlorothiazide** is a thiazide diuretic primarily used for hypertension and edema, but it lacks the specific **renoprotective effects** of ACE inhibitors in diabetic nephropathy. - While it can lower blood pressure, it does not directly reduce **proteinuria** or slow the progression of diabetic kidney disease as effectively as ACE inhibitors. *Amiloride* - **Amiloride** is a potassium-sparing diuretic that blocks sodium channels in the collecting duct and is primarily used to prevent **hypokalemia**, often in combination with other diuretics. - It does not offer the **glomerular hemodynamic benefits** or antiproteinuric effects necessary to retard the progression of diabetic renal disease. *Aspirin* - **Aspirin** is an antiplatelet agent used for cardiovascular protection, and while cardiovascular disease is common in diabetes, it does not have a direct role in **retarding the progression of renal disease**. - Its primary mechanism of action involves **antiplatelet aggregation** and anti-inflammatory effects, not modification of renal function in nephropathy.

Practice by Chapter

Antihypertensive Agents

Practice Questions

Drugs for Heart Failure

Practice Questions

Antiarrhythmic Drugs

Practice Questions

Antianginal Agents

Practice Questions

Lipid-Lowering Drugs

Practice Questions

Anticoagulants and Antiplatelet Drugs

Practice Questions

Thrombolytic Agents

Practice Questions

Drugs Used in Pulmonary Hypertension

Practice Questions

Drugs Used in Shock

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Cardiovascular Effects of Non-Cardiovascular Drugs

Practice Questions

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